The end of the Abbasid caliphate managed to be both somewhat anti-climactic and historically pivotal at the same time. In any practical sense, the caliphs had stopped being politically relevant in 945, when the Iranian Buyids seized Baghdad and put the caliphate under their “protection.” Even this was really the end of a process rather than a sudden change. The Abbasids had been losing control of their empire–to local dynasties, to the rival Fatimid Caliphate (which took North Africa from them in 909 and then Egypt in 969), and even to their own Turkish slave soldiers–for decades before that. The Turkish Seljuks swept in to Baghdad in 1055 and “liberated” the caliphs from Buyid control, but all that really meant was that the caliphs had to report to Seljuk masters instead.
To be fair, successive caliphs were able to exploit the breakup of the Seljuk Empire to assert some direct control over parts of Iraq, starting in the early-middle 12th century. But for the most part they had been reduced to a purely symbolic kind of authority–they had the ability to confer legitimacy, but no real ability to control any territory beyond their literal Iraqi back yard. So the final end of this declining dynasty wasn’t exactly a bolt from the blue.
Still, imagine the psychological shock to Muslims around the world to see Islam’s greatest city and its symbolic leader brought down like this. I don’t think we have any modern reference for it–maybe watching the Nazis march into Paris, though I don’t even think that does it justice. Constantinople’s fall to the Ottomans was probably comparable to some degree, although the Mongols were more sudden and surprising in their conquests than the Ottomans were in theirs.
It may have been particularly galling that Baghdad didn’t fall to other Muslims, or even to Christians, who at least were in the same religious ballpark. Granted, there were some Christians and even some Muslims among the Mongol forces by this point, and Buddhism was on the rise among Mongolian elites, but to a significant extent they were still an animist/pagan bunch, the kind of people Muslims going all the way back to the Quran were supposed to convert by force or kill. But the thing is, while they may not have been part of the Abrahamic world, the Mongols at their peak were perhaps the most irresistible conquering force the world has ever seen, and in 1258 they were still near that peak.
Hoping to avoid…well, to avoid what actually happened, the Abbasids started sending tribute to the Mongols in 1241, after the Mongols destroyed the Khwarazmian Empire (which had previously controlled much of Central Asia and Iran). But the caliphs still saw themselves as the successors to Muhammad, the vicegerents of God on earth–even if that didn’t have much practical weight anymore–and so the Caliph al-Mustaʿsim drew the line at personally reporting to the Mongolian court at Karakorum to pay homage to the Great Khan. That’s what the Mongols demanded, though, and in the mid-13th century the Mongols usually, one way or the other, got what they demanded. China was always first on Mongolian minds, but in 1257 the Great Khan Möngke (d. 1259) resolved to refocus on western expansion. While assigning one of his brothers, Khubilai (d. 1294), to lead their army in China, under Möngke’s close supervision, he assigned another brother, Hulagu (d. 1265), to take an army west, first to eradicate the troublesome Assassin Order (which had probably made at least one attempt on Möngke’s life) and then to capture Baghdad, unless al-Mustaʿsim finally saw the light and agreed to become a loyal vassal.
Hulagu captured the Assassins’ main fortress at Alamut in December 1256, having already accepted the surrender of the head of the order about a month earlier, and then it was on to Baghdad. Messengers were sent to al-Mustaʿsim to see if he’d reconsidered on submitting fully to Möngke’s demands. He hadn’t–and yet, inexplicably, it doesn’t appear that al-Mustaʿsim took any steps to fortify Baghdad and/or call up extra troops from the surrounding area. Why? Beats me. He may well have believed that God would finally put a stop to the Mongols’ conquests rather than allow the “capital city of Islam” to fall to them. Or maybe he was enough of a realist to figure that some extra defenses or a few more troops weren’t really going to make much of a difference.
As the Mongols approached, al-Mustaʿsim sent what soldiers he had out to meet them, to little effect. The siege itself lasted just shy of two weeks, with al-Mustaʿsim belatedly offering to negotiate (once the Mongols had already seized part of the city’s walls) and being told to get bent. It was later written that a delegation of 3000 city notables approached the Mongols to talk and were all executed for their troubles, which may be an attempt to libel the Mongols but certainly gets the point across that they were no longer in a negotiating mood. Even al-Mustaʿsim’s eventual–inevitable–unconditional surrender didn’t fully satisfy the conquerors, and the Mongols set about wrecking what had once been perhaps the most glorious city on earth. They destroyed the “House of Wisdom” and its untold number of manuscripts (more on that in a moment). They tore down and burned buildings that had stood for centuries. They slaughtered tens, possibly hundreds, of thousands of people–men, women, children, everybody.
Why was the destruction so thorough? The Mongols are often portrayed as senseless destroyers, and in general this is an unfair characterization. Don’t get me wrong, they killed a lot of people, by some estimates 5 percent of the total population of the earth by the time they were done. But killing wasn’t their goal. By and large their real interest was in making money, and to that end they actually preferred to keep cities prosperous and contributing taxes and trade goods. There were exceptions, though. A city that had an abundance of movable (or more to the point, removable) wealth could just be too tempting to resist some comprehensive looting. Baghdad certainly qualified there, though the destruction seems to have been too wanton and violent for looting to explain it all. A city that surrendered to the Mongols in exchange for soft treatment that later rebelled would almost certainly be destroyed–you know how it is, right?
But obviously that doesn’t apply in Baghdad’s case. But sometimes, especially at the start of a campaign, the Mongols might make an example of a city (especially a very large, famous city) in order to “convince” later targets that it was a bad idea to try to resist.
In Baghdad’s case, I think looting is part of it, as is the need to send a message to surrounding cities. But there may also have been a personal and/or religious motive at play. Al-Mustaʿsim’s replies to Hulagu’s messages were full of warnings about how angry God would be if Hulagu tried to march on Baghdad, and all the divine wrath that was sure to rain down on Hulagu’s head if he transgressed. Perhaps, tired of all the condescension, Hulagu was motivated to make a point about all of that. The Mongols were fond of responding to Muslim and Christian letters about how they were angering God by pointing to their constant victories and noting that this “God” of whom they wrote must clearly be on the Mongols’ side, and this particular victory would have carried more religious weight than most. There’s more though. Hulagu was known to be friendly to Christianity, and his mother, wife, and best friend/favorite general were all Nestorian Christians. So that may have had something to do with it as well. Hulagu did hand the caliphal palace over to the Nestorian Patriarch Makkikha II (d. 1265), if that suggests anything.
There are a couple of stories about what happened to poor al-Mustaʿsim. The most famous is that he was rolled up in a carpet and trampled to death by Mongolian horsemen. The Mongols supposedly believed that it was bad luck to spill the blood of a defeated ruler, so their histories are filled with the creative deaths of conquered chiefs, kings, and emperors. I’m not sure how much credence you can give reports like this, many of which were written long after the fact, relying on “sources” that may or may not have ever actually existed. There’s another legend that says the when Hulagu saw the caliph’s vast treasury, he locked al-Mustaʿsim inside with no food or water, advising him to eat and drink his gold and jewels. But this one is for sure a trope, a commentary on royal excess, where the conquering hero is astonished to find that the decadent kingdom he just conquered was hoarding wealth instead of spending it on benefiting its subjects and strengthening its army. Similar morality tales are sometimes told about Alexander the Great’s conquest of Babylon.
Baghdad rebounded somewhat as an important city under the Mongols, but it never got anywhere close to the heights it had reached before 1258. It went back into decline starting in the middle of the 16th century, when it became the most important city on the often contested frontier between the Ottoman and Safavid Empires. Neither empire saw much point to heavily investing in a city that they might lose to the other at any time, so Baghdad suffered for it. As for the Mongols, Hulagu kept moving west, until the death of Möngke in 1259 forced him to rush back east to ensure that his rights were respected in the succession process. The shell of an army he left behind tried to extend its conquests into Egypt in 1260, but that didn’t work out so well, and the Mongol Empire finally reached its western limit.
Long-term, the two biggest impacts of the sack of Baghdad were the loss of the caliphate, of course, and the destruction of the House of Wisdom, or Bayt al-Hikma. Again, the caliphate hadn’t really been more than symbolically powerful since at least the middle of the 10th century, but it was still one of the links that bound the Islamic world together–particularly after its rivals, the Fatimid Caliphate and the Umayyad Caliphate of Cordoba–had come and gone. Most Islamic rulers, no matter how independent they were in reality, pledged at least a nominal fealty to the Abbasid caliph, and in turn he ratified their authority. Coins were still struck in the caliphs’ names and the caliphs were still mentioned in Friday sermons, and these were the two most potent symbols of authority in the Islamic world at the time.
This was all sort of a pantomime, but it was still the political system of the Islamic world, and it mostly disappeared in 1258. In its absence, a kind of free-for-all ensued. Philosophers wrote treatises on the nature of political authority in this brave new world. Territories that were conquered by the Mongols made descent from Genghis Khan the replacement for the caliph’s stamp of approval as the marker of legitimacy, but that system broke down as the various Mongolian empires did, starting in the 14th century. Some local/regional rulers claimed authority in their own right. Others claimed to rule under the al-Mustaʿsim’s authority, even though he was, inconveniently, dead.
A nominal caliphate did survive Baghdad’s fall. An Abbasid cousin was spirited away to Cairo and established a “caliphate” there, but it was seen as at best a pale imitation and at worst as a puppet of the Mamluk dynasty in Egypt. Even so, some local rulers did pledge allegiance to these guys, but only in a “checking the box” kind of way, as a prerequisite for ruling. This is the “caliphate” that the Ottomans later added to their own titles when they defeated the Mamluks in 1517, which if we’re being pedantic marks the real end of the Abbasid line. But the search for a new kind of Islamic politics began, by necessity, in 1258.
If you ask me the loss of the House of Wisdom was the bigger event. The House of Wisdom began as the Caliph Harun al-Rashid’s (d. 809) private library, but eventually grew into perhaps the single greatest place of learning in the world between the 9th and 13th centuries. It attracted scholars and students from all over the world, it produced voluminous works in astronomy, math, medicine, and many other disciplines, and its translation unit was responsible for preserving works of ancient Greek and Indian scholarship that might otherwise have been lost forever. It’s safe to say that the Renaissance, for example, would not have happened the way it did (or at all, maybe) had European scholars not had access to ancient learning via the translations that were done at the Bayt al-Hikma. And the Mongols utterly destroyed it. Among their other atrocities, they dumped the contents of the library into the Tigris River, legendarily turning the water black with ink. Some of the manuscripts were saved by people who took them before the Mongols sacked the city, but it’s certain that innumerable works were irreparably lost. It’s one of those events, like the destruction of the ancient library at Alexandria, whose ultimate cost is really unknowable to us today.